auto_complete plugin for rails 2.2.2

Can anyone help me as to why I can't get this thing to work for rails 2.2.2? I get the following error when I ruby script/server:

=> Booting WEBrick... C:/Ruby/lib/ruby/1.8/yaml.rb:133:in `load': syntax error on line 5, col 11: `-a= -z (ArgumentError) ¤'         from C:/Ruby/lib/ruby/1.8/yaml.rb:133:in `load'         from C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/ initializer.rb:819:i n `database_configuration'         from C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/ initializer.rb:391:i n `initialize_database'         from C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/ initializer.rb:139:i n `process'         from C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/ initializer.rb:112:i n `send'         from C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/ initializer.rb:112:i n `run'         from C:/Users/marvin/Desktop/test_complete/config/ environment.rb:13         from C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb: 31:in `ge m_original_require'          ... 10 levels...         from C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/commands/ server.rb:4 9         from C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb: 31:in `ge m_original_require'         from C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb: 31:in `re quire'         from script/server:3